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采用原子转移自由基聚合(ATRP)方法合成了两亲性嵌段共聚物PSt-b-PAA。用1H NMR和GPC等手段对活性聚合进行了确认,对嵌段共聚物的结构进行了表征。两亲性嵌段共聚物在离子液体1-丁基-3-甲基咪唑六氟磷酸盐([BM IM][PF6])中形成胶束溶液。用透射电子显微镜(TEM)观察聚合物在离子液体中形成胶束的纳米结构。当疏水链长固定时,胶束的自组装形状主要依赖于亲水链的长度。两亲性共聚物在离子液体中可自组装成可控制结构的纳米胶束,这种纳米胶束可应用在很多领域。 相似文献
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综述了通过活性自由基聚合如原子转移自由基聚合(ATRP)、氮氧稳定自由基聚合(NMP)、可逆加成断裂链转移聚合(RAFT)等方法合成含聚乙二醇(PEG)的嵌段共聚物的研究进展,并对含PEG类嵌段共聚物在溶液中的自组装技术和在药物载体、介孔材料以及碳纳米管中的应用进行了归纳,指出含PEG的嵌段共聚物可以自组装成多种形貌,直接影响材料的性能和应用,所以这些结构有潜在的应用价值和应用前景,并且合成新的含PEG的嵌段共聚物和开发具有新型结构、形貌可控的自组装体以及新的应用领域是今后的一个热点问题,具有重要的科学研究意义和实际应用价值。 相似文献
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研究了对丙烯的高速间规活性聚合有效的Cs-对称胺芴二甲基钛络合物-干燥修饰甲基铝氧烷(dMMAO)催化剂体系对乙烯的聚合行为的影响。结果表明:乙烯常压聚合表现出稳定的聚合速率,聚合活性达到282 kg-PE/(mol-Ti·h);利用间歇聚合法进行乙烯聚合的单体转化率均达到99%以上,说明催化体系无失活现象,但得到的聚乙烯在135℃下不溶于GPC溶剂邻二氯苯中;采用先加入定量丙烯单体聚合完全结束后,再加入定量乙烯单体进行聚合的方法合成了sPP-b-PE嵌段共聚物。嵌段共聚合的结果说明乙烯聚合是以活性聚合的方式进行的。利用该催化体系还合成了丙烯-乙烯丙烯双嵌段共聚物(sPP-b-E/P)以及丙烯-乙烯丙烯-丙烯(sPP-b-E/P-b-sPP)三嵌段共聚物。 相似文献
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《染料与染色》2015,(3)
采用原子转移自由基活性聚合(ATRP)的方法,先以苯乙烯(St)为单体,α-溴代异丁酸乙酯(Ei B-Br)为小分子引发剂,Cu Br/PMDETA为催化体系,通过本体聚合制备出大分子引发剂聚苯乙烯(PS-Br)。再以PS-Br为引发剂引发第二单体甲基丙烯酸二甲氨基乙酯(DMAEMA)的本体聚合,得到PS-b-PDMAEMA-Br二嵌段共聚物,接着用PS-b-PDMAEMA-Br分别引发第三单体甲基丙烯酸甲酯(MMA)和甲基丙烯酸叔丁酯(t BMA)的本体聚合,得到三嵌段共聚物PS-b-PDMAEMA-b-Pt BMA,运用GPC、1H-NMR以及FTIR等对三嵌段共聚物进行表征;最后通过酸性水解得到PS-b-PDMAEMA-b-PMAA两亲性嵌段共聚物,并初步探究其表面活性。结果表明所得两亲性三嵌段共聚物具有一定的降低表面张力的能力,但弱于硬脂酸类小分子表面活性剂。 相似文献
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于2012年8月、11月以及2013年4月对军山湖大型底栖动物群落进行了3次调查,并且利用了Shannon-Wiener多样性指数、Margalef多样性指数和Simpson多样性指数对其水质进行了生物学评价。10个采样点中,共鉴定出大型底栖动物12种,其中:环节动物们4种,软体动物门5种,摇蚊幼虫3种。寡鳃齿吻沙蚕、半折摇蚊、河蚬以及洞穴丽蚌是现阶段军山湖底栖动物的优势种。全湖底栖动物的平均密度和平均生物量分别为362.7 ind./m2和91.09 g/m2。不同水情现存量也存在差异,平水期的密度和生物量均比丰水期、枯水期的大;枯水期的密度比丰水期大,而生物量且比丰水期小。3种指数评价结果都表明军山湖整体水质处于重污染状态。 相似文献
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分析了三氧化硫在甲苯法己内酰胺生产中的重要作用,通过对影响预混合反应和酰胺化反应的各路进料性质的分析,提出了影响反应的关键因素是循环轻相带水和亚硝基硫酸中三氧化硫波动,分析了亚硝基硫酸制备单元和酰胺化单元的操作参数、现象,并结合实验室试验,逐步提出了相应的多项解决措施,使装置实现了长期稳定运行,各项消耗数据良好,提高了装置收率和平稳率。 相似文献
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Yang Zhang Zhen Zhu Qi Xu Guohong Chen 《International journal of molecular sciences》2014,15(1):670-683
Primers based on the cDNA sequence of the goose growth hormone (GH) gene in GenBank were designed to amplify exon 2 of the GH gene in Huoyan goose. A total of 552 individuals were brooded in one batch and raised in Liaoning and Jiangsu Provinces, China. Single nucleotide polymorphisms (SNPs) of exon 2 in the GH gene were detected by the polymerase chain reaction (single strand conformation polymorphism method). Homozygotes were subsequently cloned, sequenced and analyzed. Two SNP mutations were detected, and 10 genotypes (referred to as AA, BB, CC, DD, AB, AC, AD, BC, BD and CD) were obtained. Allele D was predominant, and the frequencies of the 10 genotypes fit the Hardy-Weinberg equilibrium in the male, female and whole populations according to the chi-square test. Based on SNP types, the 10 genotypes were combined into three main genotypes. Multiple comparisons were carried out between different genotypes and production traits when the geese were 10 weeks old. Some indices of production performance were significantly (p < 0.05) associated with the genotype. Particularly, geese with genotype AB or BB were highly productive. Thus, these genotypes may serve as selection markers for production traits in Huoyan geese. 相似文献
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本文概述了三种典型的烷基化反应的特点及其研究进展,重点介绍了它们在精细化工中的重要性和应用情况。指出芳香族化合物、苯酚及吡嗪类化合物的选择性烷基化反应是精细化学品化学研究的重要方向,并分析了它们在选择性烷基化反应方面存在的问题和解决方法。 相似文献
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2014—2015年,采用高效液相色谱-质谱联用研究了5%阿维菌素水乳剂在玉米和土壤中的消解动态及最终残留情况。结果表明:阿维菌素在玉米植株和土壤中的半衰期分别为0.73~2.25d和1.65~2.76 d。施药量为15~22.5 g/hm~2,施药2~3次,阿维菌素在玉米植株中的残留量≤0.16mg/kg,而所有青玉米、熟玉米和土壤样品中均无阿维菌素检出(0.01 mg/kg)。 相似文献
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沈立平 《精细与专用化学品》2007,(Z1)
简要介绍间苯二酚的3种主要生产工艺,并分别对其优缺点进行了讨论。详细概述了美国、西欧和日本间苯二酚的应用领域及市场现状;同时还分析了国内间苯二酚在各领域的消耗和近几年的进出口情况,并对国内扩建以及新建的间苯二酚装置情况进行了全面的总结。最后对国内间苯二酚的发展提出了建议。 相似文献
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《Ceramics International》2019,45(13):15876-15882
The purpose of this study was to investigate the effects of framework thickness and cooling rate on the characteristics of fabrication defects in veneer ceramic of bi-layered lithium disilicate glass-ceramic (LDG) and zirconia. Eighty discs of 0.5-mm- and 1.0-mm-thick LDG/zirconia core were manually fabricated and veneered. Samples were divided into 8 groups according to the cooling rate, core material and core thickness, with 10 samples per group. All discs were scanned by micro-CT and 3D-reconstructed. Volume, position and sphericity of each pore defect were measured, and curves were fitted. Pore defect sizes of all samples were algorithm-fitted in two groups: 95% small defects and the rest large defects. Pore defects in veneer in LDG groups were smaller, rounder and farther from the interface with the core (p < 0.01), while large, irregular pores were observed at the zirconia interface. No differences in pore location or sphericity were found between the 0.5-mm- and 1.0-mm-thick samples in the LDG groups (p > 0.01), yet the pores in 1.0-mm-thick veneer in the zirconia core group were smaller, closer to the veneer surface, and rounder than in the 0.5-mm-thick group (p < 0.01). Pore defects in rapidly cooled samples in both LDG and zirconia frameworks were more irregular and closer to the interface with the core (p < 0.01). The pore defects were not only distinguishable between zirconia and LDG groups, but might also be related to their mechanical behaviors. The thickness of the core framework would influence the pore defect location as well as sphericity and was material-relevant. Cooling rate was deemed to be a factor in location and sphericity of pore defects in both LDG and zirconia core frameworks. 相似文献
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我国染料行业共有国家标准和行业标准254项,其中产品标准167项。近三年修订标准81项,其中新制定的标准22项。2002年35项,2003年27项,2004年19项。标准涉及染料、染料中间体产品技术指标、测试方法和有害物质的检测。其中大部分标准达到或超过了国外同类产品的先进水平。本文还分析了国外针对染料产品而发布的法令和法规,简要介绍了标准的修订概况。 相似文献